Recently, distribution of various software data, such as music data, game programs, image data (such data is hereinafter referred to as content), via networks, such as the Internet, or distributable storage media, such as memory cards, HDs, DVDs, and CDs, has become popular. The distributed content is played back once it is stored in an internal storage unit, e.g., an HD, of a user's PC (Personal Computer), recording/playback device, playback-only device, or game devices, a card-type storage device having a flash memory, a CD, a DVD, etc.
An information device, such as a recording/playback device, a game device, and a PC, has an interface through which content is received over a network or an interface through which the device accesses a memory card, an HD, a DVD, a CD, etc., a controller necessary for playback of the content, a RAM used as a memory area for a program and data, a ROM, and so on.
Various content, such as music data, image data, or a program, is invoked by a user instruction from an information device itself, such as a recording/playback device used as a playback device, a game device, or a PC, or a user instruction using a connected input unit so as to be retrieved from, for example, a built-in or removable storage medium. The content is played back by the information device or via a display, speaker, etc., connected thereto.
In general, authors or sellers of many types of software content, such as game programs, music data, and image data, hold the distribution rights thereof or the like. In distributing the content, therefore, security measures are usually taken against unauthorized duplication by providing certain usage limitations, that is, by permitting only the authorized user to use the software.
A mechanism in which content and a usage right for using the content are managed independently and are offered to a user has been proposed. In this mechanism, for example, the user must obtain encrypted content and purchase usage-right data thereof to obtain a key (content key) for decoding the encrypted content based on key data or the like, which can be obtained from the usage-right data, in order to use the content.
The usage-right data contains setting information indicating the manner that the user can use the content, so that the user can use the content within the range permitted by the permission information. Such a system has been proposed.